Test strips are used more and more for the analysis of body fluids and especially of blood and urine. Test strips are extraordinarily sensitive to moisture, which means that packaging standards for these are very high. In order to guarantee the necessary storage stability, the test strip containers must be practically completely sealed for a long period of time (at least two years). This tight sealing must also be maintained when the container is opened often (typically 50 times) in order to remove individual test strips.
In order to absorb the moisture which unavoidably gets in during the opening and closing of the test strip container, it must contain a sufficient amount of a drying agent. Nevertheless, the least possible amount of construction must be aimed for.
In spite of these requirements, the test strip packages must be easy to handle and must be easy to open and to reclose.
For a long time, test strip containers made of glass or metal and which were closed with a screw cap provided with a rubber seal were used almost exclusively. Such containers were expensive to make and their opening and reclosing was difficult.
Federal Republic of Germany patent specification No. 24 06 558 describes a test strip container and, in particular, an appropiate closure stopper of the above-described kind. A support element served to ensure sufficient sealing between the sealing beading and the associated sealing surface of the container. To accomplish this, the stopper is arranged axially at the same height as the sealing beading and, it is emphasized, an intermediate space is formed when the stopper is slackened between the support element, formed for example as a stabilizing ring, and the associated counter-surface of the hollow plug.
When a stopper constructed in this manner is introduced into the corresponding removal opening of the container body, the hollow plug is deformed comparatively easily until it lies against the support element, further elastic deformation being substantially prevented by the support element. In this way, one can achieve high pressing-on force of the sealing beading and thus good tightness.
Although it is possible, with the construction described in Federal Republic of Germany patent specification No. 24 06 558, to use closure stoppers of synthetic resin for the packaging of test strips, such packages are not satisfactory in every respect. After long storage, they are frequently difficult to open. High requirements are demanded of the tolerances of production, not only for the stoppers but also of the container bodies. Even in the case of very small deviations, it can happen that such containers develop leaks.